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LandRoverAnorak



Member Since: 17 Jul 2011
Location: Surrey
Posts: 11324

United Kingdom 
Towing Electrics Relay Wiring
Hello folks,

Can anybody point me to a wiring diagram or installation instructions for the standard LR towing electrics split charge relay? I've got one fitted to my 110 that I had to relocate yesterday and the wiring wasn't what I expected.


Click image to enlarge

The relay itself is a standard diode-equipped one and there are a number of wires, in a sheath, that disappear through the front of the seatbox and are then hidden by the matting.

The installation is a bit rough, to be honest, and I'd quite like to change it but it'd be useful to know where those wires go without having to remove all of the matting to trace them. I assumed that they might go across to the fuse box under the drivers seat but I can't see them at that end Confused Darren

110 USW BUILD THREAD - EXPEDITION TRAILER - 200tdi 90 BUILD THREAD - SANKEY TRAILER - IG@landroveranorak

"You came in that thing? You're braver than I thought!" - Princess Leia
Post #714131 24th Jun 2018 7:12am
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zsd-puma



Member Since: 09 Aug 2016
Location: Kent
Posts: 2720

United Kingdom 2010 Defender 110 Puma 2.4 USW Santorini Black
There should only be one wire that goes through the front of the seat box (green white if I remember correctly). It goes to the back of one of the dash switches to pick up an ignition live to sense it the engine is running.

Looking at your pic that's what you have, the 'number of wires' split off just after the relay the larger ones going to the battery then the single one in a protective sheath to the dash.

Installation instructions will be on Topix
Post #714154 24th Jun 2018 10:18am
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Martin
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Member Since: 02 Apr 2007
Location: Hook Norton
Posts: 6611

United Kingdom 2015 Defender 90 Puma 2.2 XS CSW Montalcino Red
That relay isn't one from the genuine LR kit - they don't use relay bases with "Ripaults" on them. Ripaults is an aftermarket electrical parts supplier.

It is either from an aftermarket (pattern) electrics kit or someone has wired up their own.

In the genuine kit the relay is used to provide a high current ignition switched supply. It isn't a "split charge" relay nor any other kind of "engine running" relay.

It takes a coil feed from one of the ignition supplies at the dash switches on a thin white and green wire (I have wired mine instead to the under seat fuse box which from 2012MY has ignition feeds to it) and relays a high current supply to the trailer socket.

LR saved themselves probably 50p by not providing a high current ignition supply at the back in the standard loom Rolling Eyes  1988 90 Td5 NAS soft top
2015 D90 XS SW
Post #714181 24th Jun 2018 1:56pm
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LandRoverAnorak



Member Since: 17 Jul 2011
Location: Surrey
Posts: 11324

United Kingdom 
Thanks chaps. I appreciate that it's not a proper split charge arrangement - I was using the term loosely.

If it's not a proper LR kit then that might explain why the wiring is slightly odd as there's definitely more than one wire going through the seat box front. The only wire that visibly emerges from the sheathing in the battery box is a red to the battery positive. However, apart form the green/white, there's another red and a brown that disappear, too.


Click image to enlarge

No matter though, as it looks like the only way to change it is to trace it under the matting and into the dash Rolling Eyes

Martin, can you ID the ignition feeds in the under seat fuse box, please? If I do change it, that would be really handy.

Many thanks. Darren

110 USW BUILD THREAD - EXPEDITION TRAILER - 200tdi 90 BUILD THREAD - SANKEY TRAILER - IG@landroveranorak

"You came in that thing? You're braver than I thought!" - Princess Leia
Post #714190 24th Jun 2018 3:17pm
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macfrank



Member Since: 05 Nov 2015
Location: somewhere in the north
Posts: 1081

Germany 2015 Defender 110 Puma 2.2 SW Keswick Green
Post #714193 24th Jun 2018 3:20pm
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Martin
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Member Since: 02 Apr 2007
Location: Hook Norton
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United Kingdom 2015 Defender 90 Puma 2.2 XS CSW Montalcino Red
The crimp quality and the fact it looks just like the original suggests it's a good aftermarket kit.

I think the red goes into the black tube and straight back out again to the relay. The black is the coil ground, white/red the relayed ignition supply. Brown to battery +.  1988 90 Td5 NAS soft top
2015 D90 XS SW
Post #714194 24th Jun 2018 3:26pm
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LandRoverAnorak



Member Since: 17 Jul 2011
Location: Surrey
Posts: 11324

United Kingdom 
Brilliant, thank you!

Looking at that, I've just realised what happens to the mystery brown and red wire, which means it is just the green white that exits the battery box Rolling Eyes Darren

110 USW BUILD THREAD - EXPEDITION TRAILER - 200tdi 90 BUILD THREAD - SANKEY TRAILER - IG@landroveranorak

"You came in that thing? You're braver than I thought!" - Princess Leia
Post #714195 24th Jun 2018 3:27pm
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LandRoverAnorak



Member Since: 17 Jul 2011
Location: Surrey
Posts: 11324

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Ah, replies crossed in the post. Thanks, Martin. Darren

110 USW BUILD THREAD - EXPEDITION TRAILER - 200tdi 90 BUILD THREAD - SANKEY TRAILER - IG@landroveranorak

"You came in that thing? You're braver than I thought!" - Princess Leia
Post #714196 24th Jun 2018 3:28pm
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Martin
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Member Since: 02 Apr 2007
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United Kingdom 2015 Defender 90 Puma 2.2 XS CSW Montalcino Red
No worries Smile

I'll dig out underseat info for you tomorrow.  1988 90 Td5 NAS soft top
2015 D90 XS SW
Post #714197 24th Jun 2018 3:30pm
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zsd-puma



Member Since: 09 Aug 2016
Location: Kent
Posts: 2720

United Kingdom 2010 Defender 110 Puma 2.4 USW Santorini Black
Martin wrote:
That relay isn't one from the genuine LR kit - they don't use relay bases with "Ripaults" on them. Ripaults is an aftermarket electrical parts supplier.


Ripaults Ltd used to be one of Land Rover's suppliers, you find their name written all over wiring loom labels on Rover Group products. I'm pretty sure my genuine kit has Ripaults on the relay base. The easiest way to check if it's a factory harness though is wether the towing socket is Land Rover Branded on the flap.
Post #714211 24th Jun 2018 4:46pm
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Rossy110



Member Since: 26 Mar 2018
Location: Aberdeenshire
Posts: 30

Scotland 2014 Defender 110 Puma 2.2 XS CSW Sumatra Black
Sorry to butt in gents but if the green and white ignition supply is not connected then the high current switch supply is always off? Is the main purpose of this to run a fridge etc during travel. And will the lights and indicators still work fine, the only reason I'm asking is if just fitted a LR wiring loom and not fitted this yet and need to pick up a caravan tomorrow. Thanks
Post #714243 24th Jun 2018 7:33pm
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Martin
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Member Since: 02 Apr 2007
Location: Hook Norton
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United Kingdom 2015 Defender 90 Puma 2.2 XS CSW Montalcino Red
If you don't fit that wire it has no effect on the lights whatsover, it simply means that the ignition switched supply to the trailer socket is not live - pin 10 of a 13 pin socket or pin 6 of the 12S socket.

If you don't need the fridge powered then you have no problem.

I ran mine for 2 years+ without it connected as well Whistle Laughing  1988 90 Td5 NAS soft top
2015 D90 XS SW
Post #714245 24th Jun 2018 7:37pm
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Rossy110



Member Since: 26 Mar 2018
Location: Aberdeenshire
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Scotland 2014 Defender 110 Puma 2.2 XS CSW Sumatra Black
Happy days, I was worried for a minute that the whole loom would not work. Smile
Cheers for the swift reply Martin
Post #714247 24th Jun 2018 7:44pm
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zsd-puma



Member Since: 09 Aug 2016
Location: Kent
Posts: 2720

United Kingdom 2010 Defender 110 Puma 2.4 USW Santorini Black
No unlike some cars with can bus wiring it's just to flick the relay on for the fridge power and I think caravan battery charging.

If you do want to run the fridge to test it when picking the caravan up, just connect the green/white wire to the battery temporarily.

And for anyone reading this who just wants the superior 13 pin socket for a trailer - you don't even need to run any of the wires through to the front at all to make the lights work.
Post #714252 24th Jun 2018 7:58pm
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blackwolf



Member Since: 03 Nov 2009
Location: South West England
Posts: 17450

United Kingdom 2007 Defender 110 Puma 2.4 DCPU Stornoway Grey
If you have a heated windscreen there is a proper "engine running" signal available in the offside seatbox, rather than using an "ignition on" signal. Due to the exceptionally high current it draws, the HFS will only work when the engine is running and the HFS relay uses a signal from the IPAC to detect this.

The result is similar I suppose to a VSR but probably more reliable.
Post #714278 24th Jun 2018 9:27pm
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